1. Field of the Invention
The present invention relates to a method and apparatus for manufacturing a legged annular member. More specifically, the present invention relates to a manufacturing method and manufacturing equipment for a legged annular member having a ring-like annular part and at least one leg formed on an outer peripheral side of the annular part generally perpendicular to the annular part.
2. Description of the Related Art
Japanese Patent Application Publication No. JP-A-2001-105085, for example, proposes a conventional method for manufacturing this type of legged annular member. The proposed manufacturing method includes a preform forming process and a trimming process. In the preform forming process, a preform of a member with legs is formed by executing back side extruding formation of a disc-shaped blank (raw material) to form a bottom part, a plurality of leg parts with differing widths (thicknesses) along an outer peripheral surface of a side surface side of the bottom part, and a film part extending between the respective leg parts. In the trimming process, a center portion of the bottom part and the film part of the preform formed in the preform forming process is trimmed.
However, burrs sometimes form on the leg parts when the film part is trimmed in the trimming process according to the above-described manufacturing method for a legged annular member. Such burrs in the past were removed by hand, and a relatively long period of time was needed for completion of the legged annular member. Also, when the film part is trimmed in the trimming process, the leg parts sometimes fall slightly inward and necessitate a process to expand an inner diameter of the leg parts, which is separate from the process for removing burrs from the leg parts.